How It Works
How Diatomaceous Earth Works
How Diatomaceous Earth Works?
One vulnerability most insects share is the danger of drying out. Their exoskeleton – the hard outer “shell” most adult insects have – safeguards their internal moisture. Inert (“safe”) dusts such as DE are effective pesticides because they absorb water – protecting fats and oils from the epicuticle
(outer layer) of the exoskeleton, thereby disabling its moisture-retaining ability. The insect essentially dehydrates. DE works mechanically, not chemically, and it will remain effective as long as it’s undisturbed.
DE is unique among inert dusts because of its abrasive properties.
The microscopically sharp edges of diatoms abrade the epicuticle, enhancing the dehydrating effect.
The use of inert dusts to control insects has been around for thousands of years.
Ancient cultures around the world used them to protect stored grains against pantry pests like moths and beetles. The same mode of action is used by birds or other animals that take dust baths – they are ridding themselves of their arthropod parasites.
In our extremely arid climate, DE’s effectiveness is maximized because it is not limited by high humidity, and insects will desiccate more rapidly for lack of readily available water. Unlike most synthetic pesticides, DE won’t break down in the presence of sun or heat, so it provides long lasting control.
How Safe Is DE?
DE may be processed and graded for pest control on grains (“food grade”)orfor crack and crevice type pest treatments. DE for crack and crevice pest treatments includes trace amounts of pyrethrin pesticides and other chemical synergists, whereas food grade DE is 100% diatomaceous earth without any added chemicals. Both food grade DE and that labeled for pest control will work to kill pests through desiccation; however, the crack and crevice DE containing pesticides and other ingredients gives an additional rapid kill effect.
Food grade DE is non-toxic and high purity forms are safe for human consumption, sold under the general name “Fossil Shell Flour”. It is even allowable on “organic” labeled foods by the United States Department of Agriculture. The names and labels for food grade DE and general pest control DE are often very similar, so labels should be read carefully.
DE is U.S. EPA registered under several different product names; however, for the purposes of pest control, DE is rated with a “caution” label (the lowest level of toxicity based on a three-tier system assigned by the EPA: caution-lowest toxicity, warning-middle, danger-highest toxicity).
NOTE: Pool filter grade DE is processed differently – it is not amorphous, but rather contains crystallized silica (formed when DE is exposed to high heat). Such forms of DE are carcinogenic and not recommended for use in pest control.
Because DE is a fine dust, even food-grade forms may pose a hazard to health if inhaled.
If dusting large areas best to use a dust mask.
https://www.fossilpower.com.au/research/
http://www.regional.org.au/au/asa/2010/crop-production/soil-biology-nutrition/7055_matichenko.htm